explanation of the westward intensification of the Gulf Stream and the 
Kuroshio by this idea demonstrated several years ago by Henry Stonnel 
(1948), Walter H. Munk (1950) and Koji Hidaka (1951). A theory of upwell~ 
ing recently worked out by Hidaka (1953) 48 also based on this consider~ 
ation. The present discussion also consists of an application of this 
concept and treats the surface form of the sea off a straight coast 
developed by the effect of steady winds blowing in a certain direction 
in a finite band within a certain distance from the coast. 
The theory of aarinees of water on the coast by the action of the 
wind was first treated by V. W. Ekman. Ilis explanation consisted of the 
fact that very close to the coast the steady flow of water driven by wind 
toward or away from the coast just balances the flow due to the slope 
current produced by the piling-up on or taking-away of water from the 
coast. This seems to have been successful in predicting the slope and 
of the water surface approximately. But since his theory assumes that the 
velocity and surface slope are uniform in horizontal directions the diffi-e 
culty is that of how far from the coast the predicted slope is. Present 
research shows that the slope and level change of the water surface occurs 
mostly belcw the wind zone only. Further, Ekman's theory is Gani to sey 
how the height of the sea surface varies as we are removed away from the 
coast. This is mathematically impossible because only the vertical 
momentum transfer is taken into account and the velocity components and 
slcpe of water surface are functions of vertical coordinates x alons. 
In order to discuss the horizontal variation of these quantities, however, 
4% is necessary to consider horizental mixing. 
The following theory is nothing but a modification of Honan's theory 
of wind-driven currents made by introducing the effect of horizontal eddy 
cadeo 
